Certain disease states require treatment using one or more different medicaments. Some drug compounds need to be delivered in a specific relationship with each other in order to deliver the optimum therapeutic dose. This invention is of particular benefit where combination therapy is desirable, but not possible in a single formulation for reasons such as, but not limited to, stability, compromised therapeutic performance, and/or toxicology.
For example, in some cases it might be beneficial to treat a person suffering from diabetes with a combination of a long acting insulin along with a glucagon-like peptide-1 (GLP-1). This GLP-1 is derived from the transcription product of the proglucagon gene. GLP-1 is found in the body and is secreted by the intestinal L cell as a gut hormone. GLP-1 possesses several physiological properties that make it (and its analogs) a subject of intensive investigation as a potential treatment of diabetes mellitus.
A number of potential problems can arise when delivering two active medicaments or “agents” simultaneously. As just one example, the two active agents may interact with each other during the long-term, shelf life storage of the formulation. Therefore, there are certain advantages to storing the active components separately and then potentially combine them at the point of delivery, e.g. injection, needle-less injection, pumps, or inhalation. However, any potential process for combining the two or more agents needs to be straight forward and convenient for the user to perform reliably, repeatedly, and safely.
One further concern is that the quantities and/or proportions of each active agent making up the potential combination dose or therapy may need to be varied for each user or at different stages of their therapy. Again, as just one example, one or more active agents may require a titration period to gradually introduce a patient to a “maintenance” dose. A further example would be if one active agent requires a non-adjustable fixed dose while the other agent is varied in response to a patient's symptoms or physical condition. This potential concern could mean that pre-mixed formulations of multiple active agents may not be suitable as these pre-mixed formulations would have a fixed ratio of the active components, which could not be varied by the healthcare professional or user.
Additional concerns may arise where a multi-drug compound therapy is required, because certain users may not be able to cope with having to use more than one drug delivery system or make the necessary accurate calculation of the required dose combination. This is especially true for users with dexterity or computational difficulties.
Accordingly, there exists a strong need to provide devices and methods for the delivery of two or more medicaments in a single injection or delivery step that is simple and safe for the user to perform and that also tends to reduce a patient's anxiety towards injections and/or needles.